"Hearst Magazines and Yahoo may earn commission or revenue on some items through the links below." Hydraulic pressure controls spider leg movements, allowing the arachnids to straighten and curl their ...

As they twitch their legs and move their eyes, Evarcha arcuata, a species of jumping spiders, show something reminiscent of rapid eye movement sleep, researchers report Monday in the Proceedings of ...

Researchers found jumping spiders, known for their acrobatic hunting, exhibiting signs of R.E.M. sleep, but it is unknown whether they dream, or even sleep. By Carolyn Wilke By day, jumping spiders ...